The present invention relates to processing apparatuses which perform a substrate processing while transferring a substrate.
Conventionally, a substrate transfer apparatus (such as, a moving stage) has been used in performing a substrate processing while moving a processing unit such as a print head, and a substrate relative to each other.
In such a substrate transfer apparatus, the flatness and smoothness of a mounting surface for mounting a substrate is required in order to control a positional relationship between the processing unit and the substrate with high accuracy. Conventionally, the required flatness was around 100 μm, while in recent years a higher flatness (50 μm or less) has been required.
A method is known wherein a material (such as, granite) having a high hardness, is polished to form a substrate-mounting table.
However, granite is heavy in weight, and in order to move the substrate-mounting table at a high speed, a high-power moving unit and a control unit are required, thereby resulting in an increase in equipment cost and running cost (driving power or the like). Moreover, with an increase in the size of the substrate in recent years, the size of the mounting table has also increased; and thus, a reduction in the weight of the mounting table has been further required.
If the thickness of the mounting table made of granite is reduced, the strength of the mounting table decreases although the weight thereof can be reduced. Moreover, if the mounting table is thinned, the mounting table will bend when the mounting table is supported by a support shaft which is disposed upright on an air bearing (or wheel).
In order to improve the flatness of the mounting surface, prior to attaching the mounting table to the support shaft, the mounting table is usually disposed in a processing table, which is wider than the mounting table so as to polish the mounting surface. However, even if the flatness of the mounting surface is set 50 μm or smaller by polishing, and when the mounting table bends due to its attachment to the support shaft, the flatness of the mounting surface will exceed 50 μm.
Such problems are disclosed in, for example, JPA No. 07-311375 and JPA No. 2005-114882.